JPH09507898A - Catalytic muffler device - Google Patents

Abstract

(57) Summary A muffler for coupling to an exhaust port of an internal combustion engine includes a housing, a first hollow body within the housing, a catalytic device within the first hollow body, and a second hollow body within the housing. . The first hollow body has an inner surface defining a first chamber and an inlet adjacent the exhaust port for admitting exhaust gas into the first chamber. The exhaust gas is exothermically treated as it flows through the catalyst in the first chamber in a direction away from the engine and passes through the outlet of the first hollow body to the second chamber. The second chamber is formed by the inner surface of the second hollow body and the outer surface of the first hollow body. The treated exhaust gas flows over the outer surface of the first hollow body towards the engine through the second chamber and through the outlet of the second hollow body to the third chamber. The third chamber is formed by the outer surface of the second hollow body and the inner surface of the housing. The outlet of the second hollow body is provided with a louver for directing exhaust gas away from the engine in the third chamber. After expansion and mixing in the third chamber, exhaust gas is discharged from the third chamber through the outlet of the housing adjacent to the engine.

Description

Detailed Description of the Invention Catalytic muffler device Field of the invention   The present invention relates to mufflers for internal combustion engines, and more particularly to air blowers, Flexible line trimmers, edge trimmers, chainsaws, and other portable equipment The present invention relates to a catalytic muffler device for an internal combustion engine used in a tool. BACKGROUND OF THE INVENTION   To reduce harmful components of exhaust gases such as hydrocarbons and carbon monoxide Catalytic element for muffler for small two-stroke internal combustion engine used for portable tools Alternatively, it is known to use catalytic devices. For example, hydrocarbon to carbon dioxide And catalytic converters that convert to water cause exothermic chemical conversions. Typically Exhaust gas is exhausted after it enters the catalytic device at about 600 degrees Celsius (° C) and undergoes chemical conversion. The temperature of the gas rises to about 1000 ° C in the catalytic device.   Catalytic devices are typically relatively small. Because it is a portable tool This is because the muffler used for must be compact and lightweight. Touch The media system is small, and the exhaust gas is typically two-stroke engines. Due to its wealth, a complete conversion of the harmful constituents of the exhaust gas cannot be obtained. This thing This is a problem in regulations that increasingly demand very low exhaust emission power levels. in addition, Exhaust gases, through the exhaust outlet or at a temperature high enough to ignite themselves. Oxygen-containing ambient air is passed through the gears at the intermediate surface of the partition of the hula housing. It may ignite when it comes into contact with the air. Smell that you can carry with you Workers are at risk from both hot exhaust gases and ignition of the exhaust gases. It is.   United States Patent No. 4, whose disclosure is expressly incorporated herein in its entirety. 867,270 discloses a muffler for a two-cycle engine having a catalytic device. I have. The catalytic device is housed so that it is spaced from the housing wall on all sides. Located within a gas-sealed hollow body mounted within the housing. Untreated exhaust gas is medium The outer surface of the hollow body for cooling the hollow body before entering the cavity and passing through the catalytic device Pass through one part of. Hollow body reduces self-ignition of hot treated exhaust gas To have an outlet portion that is tapered in the direction of flow.   United States Patent No. 4, whose disclosure is expressly incorporated herein in its entirety. No. 890,690 discloses a muffler for a two-cycle engine having a catalytic device. I have. The catalyst and the partition wall establish two chambers in the housing. Exhaust gas is first It enters one chamber and passes through the catalytic device to the second chamber. Treated exhaust gas is second Exit the housing through the chamber outlet. Treated exhaust gas on the partition wall It is arranged downstream of the intermediate surface of the housing such that it cannot be returned. Exhaust gas on the partition wall Is provided with a bypass hole so that a part of it can bypass the catalytic device.   United States Patent No. 5,0, whose disclosure is expressly incorporated herein in its entirety No. 48,290 discloses a muffler for a two-cycle engine having a catalytic device. You. The catalytic device is placed in spaced tubes within the muffler housing. Engine The inner end of the tube facing the exhaust port has less heat transfer to the engine Closed by the convex perforated plate. The outer end of the tube is covered by a lid with a cooling plate Closed. Exhaust gas enters the housing and travels through the perforated plate to the catalytic device . After passing through the catalytic device, the exhaust gas is deflected by the lid through the side opening of the pipe to the outlet pipe. Is done.   These mufflers reduce the exhaust gas outlet temperature or muffler housing surface temperature. While gaining, they may have relatively high exhaust emission power levels. did Therefore, a relatively low exhaust emission power level and a relatively low exhaust gas outlet temperature Compact and light for 2-cycle engine with muffler housing surface temperature A large amount of muffler is required. In addition, the muffler provides good sound reduction and good entrainment. It should maintain gin performance and be reliable, inexpensive and easy to manufacture. Summary of the Invention   The present invention is coupled to an exhaust port of an internal combustion engine that solves the above-mentioned problems of the related art Provide a muffler to do. A muffler according to the present invention is a housing, the housing A first hollow body in the interior and a catalyst in the first hollow body for treating the exhaust gas exothermically Including equipment. The first hollow body is an inner surface forming a first chamber and an outer surface forming a second chamber. Has a face. The inlet communicates the first chamber with the exhaust port for introducing exhaust gas into the first chamber In order to do so, it is provided in the first hollow body. The first hollow body also moves from the first chamber to the second chamber. It has an exit for passing through. In the second chamber, the treated exhaust gas in the second chamber is Flow across the outer surface of the first hollow body in the second chamber so as to reach the outlet of the second chamber in terms of quality. As described above, an outlet opposite to the outlet of the first hollow body is provided. Brief description of the drawings   These and other features of the invention will be apparent in connection with the following description and drawings. It becomes   1 is a portable with a two-stroke internal combustion engine and a muffler according to the invention. Front view showing in cross section the power head of a different tool;   FIG. 2 is a partial plan view showing the muffler partially in cross section;   FIG. 3 is a sectional view of the muffler taken along line 3-3 in FIG. 2;   FIG. 4 is a cross-sectional view of the exhaust gas flow path through the muffler taken along line 4-4 in FIG. 3;   FIG. 5 is a sectional view of the muffler taken along line 5-5 in FIG. 2;   FIG. 6 is a partial front view partially showing the exhaust outlet of the muffler in a cross section. . Detailed description of the preferred embodiment   FIG. 1 shows a portable tool, especially a chain, containing a muffler according to the invention. A saw power head 10 is shown. The power head 12 is, for example, a line trimmer, Blower, hedge trimmer, edge trimmer, lawn mower, chain saw and jet Power tool for portable tools driven by an internal combustion engine such as a snow blower This is a representative example of the code.   The power head 10 is a two cycle, single cylinder, air cooled internal combustion engine 12. It is driven by power. The engine 12 includes a plurality of externally arranged cooling fins 16. The cylinder 14 is included. Preferably, the cylinder 14 is substantially light weight. And heat from the inside of the cylinder 14 is transferred to the cooling fins 16 Made from conductive aluminum. In the usual way, the piston 18 Generally reciprocates along axis 20 in bore 22 of cylinder 14. Fixie The reciprocating movement of the shaft 18 is carried by the rod 24 rotating the crank pin 26 until the axis 20 is reached. It is converted into rotation of the crankshaft instead. The crankshaft has a counterweight of 28 and And the crank pin 26 covers it.   The top edge of piston 18 controls the opening and closing of window 30 to exhaust port 32. Exhaust port The port 32 is directly connected to the inlet 34 of the muffler 11. Exhaust gas from the hole 22 is exhausted Exhausted through the air port 32 and directed into the muffler 11 through the inlet 34. The muffler 11 is directly secured to the cylinder 14 using mounting bolts 36. Other types of fasteners or retention methods can be used, such as springs.   As best shown in FIG. 4, the exhaust port 32 is reinforced with a steel sleeve 38. To form a boundary 40 around the sleeve 38. Sleeve 38 And void 40 has a lower thermal efficiency than cylinder 14. Void with the sleeve 38 40 thus slows the rate of heat transfer from the exhaust gas to the walls of the cylinder 14. Acts as an insulator. Ameri whose disclosure is specifically incorporated herein in its entirety. United States Patent Application No. 08 / 072,164 discloses more information on such sleeves. It should be considered with regard to a lot of information.   In order to reduce the heat that the heat shield 42 radiates from the muffler 11 to the cylinder 14, It is arranged between the hula 11 and the cylinder 14. The heat shield 42 is preferably good Made from aluminum for heat dissipation. The heat shield 42 allows passage of exhaust gas. Aligned with exhaust port 32 and muffler inlet 34 to accommodate Includes aligned exhaust openings. Bolt 3 for holding muffler 11 against cylinder 14 6 extends through openings in the heat shield 42 to maintain proper alignment. Heat shield The surface of 42 impedes the flow of cooling air through the cylinder 14 and muffler 11. It is preferably approximately equal to the muffler 11 so as not to do so.   The heat shield 42 and the heat shield 42 shield the heat transfer to the cylinder 14. By an insulator or gasket 44 to introduce an air layer between it and the binder 14. Are spaced apart from the cylinder 14. Gasket 44 is preferably Made of steel or other material with some degree of insulation. Gasket 44 is exhaust Exhaust ports 32, heat shield exhaust openings, and muffs to allow the passage of gas. Aligned with the la inlet 34 during assembly. Muffler for cylinder 14 The bolts 36 that hold 11 are the openings in the gasket 44 to maintain proper alignment. Extend through.   As seen in FIGS. 2-6, the muffler 11 includes a housing 46, a catalyst. Tubular structure 48, reflector 50, flame suppression screen 52, and exhaust outlet deflector or The louver 54 is included. The muffler housing 46 has a concave first and second opposing surface. Made of complementary shell members 56, 58 in the shape of a circle. The shell members 56 and 58 are made of sheet metal. It is formed by stamping a rigid material. Material generated by engine It must be able to withstand the extreme temperatures of the exhaust gases that are exhausted.   As seen in FIG. 5, the first shell member 56 includes a rear wall 60, a side wall 62, and a flap. Includes lunge 64. The muffler inlet 34 is in fluid communication with the exhaust port 32. Is arranged on the rear wall 60. The rear wall 60 is also used for mounting the bolt 36. An opening 66 is included. The side wall 62 extends vertically from the periphery of the rear wall 60. Muffler out The mouth 68 (FIG. 4) is an upper portion of the first shell member 56 and is substantially adjacent to the rear wall 60. 2 are arranged. The flange 64 extends outward from the outer end of the side wall 62 opposite the rear wall 60. Extend.   The second shell member 58 includes a front wall 70, a side wall 72, and a flange 74. Three A recess 76 is formed in the front wall 70 and has an opening 78 for the mounting bolt 36. The side wall 72 extends vertically from the periphery of the front wall 70. The flange 74 is opposite the front wall 70 Around the flange 64 of the first shell member 56 extending outwardly from the end of the side wall 72. The shell members 56 and 58 are attached to the muffler 1 in a gas-tight manner by caulking with the muffler 1. Hold 1 together. The shell members 56, 58 are generally, for example, welded or machined. It may also be attached by other attachment means having a gas-tight seal such as a static fastener. it can.   The housing 46 can also have generally double walls. Double wall is inner wall And an outer wall that is spaced from the inner wall to form a void. Wear. The void may be filled with a high temperature resistant insulating material. Double-walled housing The outside of the housing 46 by reducing the ability to conduct heat from within the ring 46. It is possible to reduce the skin temperature on the surface.   As best seen in FIGS. 3-5, the catalyst tube assembly 48 is within the housing 46. And includes a first hollow body 80, a catalytic device 82, and a second hollow body 84. Each component of the catalyst tubing structure must withstand the extreme temperatures of the sheet metal or exhaust gas. It is formed by stamping a rigid material such as another material that can Catalyst tube The central axis 85 of the structure 48 is coaxial with the exhaust port 32. The first hollow body 80 is substantially A length dimensioned to extend from the rear wall 60 of the upper first shell member 56 to the reflector 50. It has a tubular shape with a thickness. The first hollow body 80 is dimensioned to surround the muffler inlet 34. It has a prescribed diameter. The plurality of outlets 86 are close to the front wall 70 of the second shell member 58. The first hollow body 80 is in contact with and opposite the inlet 34 and adjacent to the outer end of the first hollow body 80. Spaced around the perimeter of. As shown in FIG. 3, the illustrated embodiment has seven Circular outlets 86, four of which are around the bottom of the first hollow body 80, etc. Are spaced closely and three are equally spaced around the top of the first hollow body 80. Placed.   As seen in FIGS. 3-5, the catalytic device 82 is adjacent to the inlet 34 and exits. Located inside the first hollow body 80 at the inner end of the first hollow body 80 opposite the mouth 86. . The catalytic device 82 is generally sized to fill the entire cross section of the first hollow body 80. And preferably an opening 88 extending axially in the central axis 85 of the catalyst tube assembly 48. Include. Generally, a plurality of axially extending openings may be provided.   The second hollow body 84 has a tubular shape having a length substantially equal to the length of the first hollow body 80. And surrounds the 1st hollow body 80. The second hollow body 84 is longer than the diameter of the first hollow body 80. Has a large diameter. As best shown in FIG. 3, it extends inwardly in three radial directions. A recess 90 is formed in the second hollow body 84. The recess 90 is at the periphery of the second hollow body 84. Spaced and dimensioned to receive mounting bolt 36. Recess The diameters of 90 and the second hollow body 84 are such that the first hollow body 80 is centered and the catalyst tube structure is It is dimensioned to be held in alignment with the central axis 85 of 48. Best in Figure 4 As seen in FIG. 2, the outlet 92 is adjacent to the muffler inlet 34 and is inward of the second hollow body 84. Spaced around the circumference of the second hollow body 84 at the ends. The illustrated embodiment is the second It includes four outlets 92 spaced around the circumference of hollow body 84. Exit Formed on each of the 92 is the outer end of the second hollow body 84 opposite the muffler inlet 34. A deflector or lever shaped to direct the exhaust gas exiting the outlet 92 in the onward direction. It is a server 94.   The reflector 50 is substantially flat and has a shape substantially equal to the cross section of the second shell member 58. Have a shape. The reflector 50 must withstand the extreme temperatures of sheet metal or exhaust gases It is formed by stamping a rigid material such as another material that can Almost vertical A lip 96 extending to the periphery is provided around the reflector 50. The reflector 50 is mounted on It includes an opening 98 for the belt 36. As best seen in Figure 4, the arcuate A first ridge 100 is formed in the reflector 50 and extends from the outer surface of the reflector 50. The first ridge 100 has a second ridge for positioning the reflector 50 within the housing 46. Sized and shaped to cooperate with a recess 76 in the front wall 70 of the shell member 58. You. A recess 76 in the front wall 70 of the second shell member 58 spaces the reflector 50 from the front wall 70. The temperature of the front wall 70 by placing exhaust gas in direct contact with the front wall. Reduce. An arcuate second ridge 102 is formed in the reflector 50 and It extends from the inner surface of zero. The second ridge 102 is located within the housing 46 and is a catalyst tube assembly 48. Sized and shaped to cooperate with the second hollow body 84 for centering the You.   The flame suppression screen 52 has a substantially tubular shape having a length substantially equal to that of the second hollow body 84. It is. The flame suppression screen 52 has first and second hollow flame suppression screens 52. Formed by the outer surface of the louver 94 of the second hollow body 84 so as to be coaxial with the bodies 80, 84 Has a diameter slightly larger than the diameter given. The flame suppression screen 52 is preferably Made from stainless steel mesh with 0.020 inch or smaller opening It is.   The exhaust outlet louver 54 is adjacent to the exhaust outlet 68 of the first shell member 56 of the housing 46. It is attached to the housing 46 in contact therewith. The louver 54 is separated from the engine cylinder 14. Shaped to direct the exhaust gas exiting the exhaust outlet 68 in a directed direction. Shown in Figure 6 As described above, the opening 104 has a low louver 54 created by the exiting exhaust gas. An exhaust outlet louver 54 is arranged to allow the atmosphere to enter the pressure zone. Atmosphere is exhaust gas The temperature of the exhaust gas that is mixed with the exhaust gas is reduced. Exhaust outlet louver 54 or The exhaust outlet 68 also comprises a spark suppression screen. Spark suppressor 105 screen 52 is preferably stainless steel with an aperture of 0.020 inches or less Made from mesh.   In the muffler 11, the inner end of the first hollow body 80 and the inner end of the second hollow body each have a first shell. The catalyst tube assembly 48 is provided in the first shell member 56 so as to contact the rear wall 60 of the body member 56. Assembled by placing. The flame suppression screen 52 is the corner of the catalyst tube assembly 48. And the rear wall 60 of the first shell member 56. Reflector 50 is in the middle Positioned so as to abut and close the outer end of the hollow body 80 and the outer end of the second hollow body 84. To be decided The outer end of the second hollow body 84 is located in the second raised portion 102 of the reflector 50. The catalyst tubing assembly 48 is positioned and oriented relative to the reflector 50. The second shell member 58 is disposed on the reflector 50 and the first ridge 10 of the reflector 50. The reflector 50 relative to the housing 46, positioned by the recess 76 in the zero. Position and orient. The flange 74 of the second shell member 58 has the first shell member 56. The flange 64 is crimped. The shell members 56, 58 are thus the catalyst tube assembly 48. Tighten the reflector 50 and flame suppression screen 52 in place.   As best seen in FIG. 4, the muffler 11 includes a first, second and third chamber 1. 06, 108, 110. The first chamber 106, which is cylindrically shaped, has a first hollow Defined by the inner surface of body 80, reflector 50, and back wall 60 of housing 46. You. The second chamber 108, which is formed in an annular shape, is formed on the outer surface of the first hollow body 80, the second hollow body 8 4, the reflector 50, and the back wall 60 of the housing 46. The third chamber 110 includes the outer surface of the second hollow body 84, the reflector 50, and the inside of the housing 46. It is defined by the surface.   As shown in FIG. 4, the exhaust gas adjacent to the exhaust port 32 passes through the inlet 34. And flows into the first chamber 106 at a temperature of about 600 ° C. Exhaust to the first chamber 106 Gas enters and flows through the catalytic device 82 in a direction away from the engine cylinder 14. . An initial emission reduction occurs in the catalytic device 82. After passing through the catalyst device 82, First chamber radially away from inlet 34 and exhaust port 32 through outlet 86 Exit 106 and enter second chamber 108. When the exhaust gas enters the catalyst device 82 At temperatures very high compared to its temperature, typically about 900 to about 1000 ° C. The media device 82 is removed. The reflector 50 closes the outer end of the first chamber 106 and heats it up. The muffler 1 is prevented by preventing the treated exhaust gas from contacting the front wall 70 of the second shell member 56. Maintain a relatively low surface temperature in front of 1.   In the second chamber 108, the exhaust gas is the very hot outer surface 1 of the first hollow body 80. Direct it toward the engine cylinder 14 so that it flows over the entire circumference of 12 It is. The second chamber is a relatively narrow annular shaped flow path for exhaust gas. Additional release In the second chamber 108, a decrease in the amount of thermal reaction occurs due to the high temperature of the outer surface 112 of the first hollow body 80. It is caused by. The temperature required to continue combustion in the second chamber 108 Is at least about 750 ° C. Yet another emission reduction in the second chamber 108 It is further advantageous to provide a catalyst coating on the outer surface 112 of the first hollow body 80 to obtain. May be convenient for you.   The exhaust gas is discharged from the outlet 92 of the second hollow body 84 adjacent to the engine cylinder 14. Pass through the second chamber 108 and then into the third chamber 110. Second hollow body 84 The server 94 directs exhaust gas away from the engine cylinder 14. Exhaust gas Is a flame suppression screen 5 to help ensure that the flame does not leave the muffler 11. Pass 2 In the third chamber 110, the exhaust gas is expanded and mixed thoroughly. . Exhaust gas passes through the muffler outlet 68 to the exhaust outlet louver 54, Retire from Jing 46. Since the exhaust gas passes through the opening of the exhaust outlet louver 54, Atmosphere is drawn into the exhaust outlet louver 54 through the opening 104 and pumps the exhaust gas. Mix with the exhaust gas to cool it further. Exhaust gas is discharged from the exhaust outlet louver 54 and The spark suppression screen 105 is removed and the cooling fins 16 of the engine cylinder 14 are removed. Emitted to the atmosphere in a direction away from.   Although a particular embodiment of the invention has been described in detail, it should be understood that the invention Clarity is not limited in scope, and the spirit of the claims appended hereto and It is meant to encompass all changes and changes that are within the term.

Claims (1)

[Claims]   1. In a muffler for coupling to the exhaust port of an internal combustion engine,   housing;   An inner surface partially defining the first chamber, an outer surface partially defining the second chamber, an internal combustion engine Between the first chamber and the exhaust port for introducing exhaust gas from the first chamber to the first chamber. With exhaust fluid communication, and treated exhaust gas from the first chamber to the second chamber A first hollow body in the housing having an outlet for communicating therewith;   Comprising a catalytic device in the first chamber for exothermic treatment of the exhaust gas; and Exhaust gas that has been treated in the second chamber substantially causes the second chamber to cover the outer surface of the first hollow body. Having an outlet opposite the outlet of the first hollow body to flow across it. A characteristic muffler.   2. The inlet to the first hollow body is located adjacent the exhaust port and The outlet from the first hollow body is forward in the direction in which exhaust gas leaves the exhaust port. Note that it is arranged apart from the exhaust port so as to flow through the first chamber. The muffler according to claim 1.   3. Furthermore, an inner surface that partially defines the second chamber and an outer surface that partially defines the third chamber. Surface and an outlet for communicating exhaust gas from the second chamber to the third chamber. It consists of a second hollow body in the housing, the outlet of the second hollow body being the treated exhaust. Arranged so that gas vapor flows substantially across the outer surface of the first hollow body. The muffler according to claim 1, wherein:   4. The outlet of the second hollow body is in the first chamber to the second chamber in a substantially opposite direction of flow. Featuring a louver adapted to direct the treated exhaust to The muffler according to claim 3.   5. The inlet of the first hollow body is located adjacent to an exhaust port and 1 The outlet of the hollow body is arranged in the direction in which the exhaust gas is substantially separated from the exhaust port. Characterized by being arranged opposite to the exhaust port so as to flow through one chamber The muffler according to claim 3.   6. The direction in which the exhaust gas from the outlet of the second hollow body is substantially directed toward the engine An end of the second hollow body adjacent to the engine so as to flow through the second chamber The muffler according to claim 4, wherein the muffler is arranged in a part.   7. The treatment is performed in a direction in which the outlet of the second hollow body is substantially separated from the engine. A louver adapted to direct exhaust gas only. A muffler according to claim 6.   8. Furthermore, it comprises a flame suppression screen that crosses the outlet of the second hollow body. The muffler according to claim 3, wherein:   9. The first and second hollow bodies are tubularly shaped and the muffler is further forward A reflector for closing the ends of the first and second hollow bodies opposite the engine The muffler according to claim 3, characterized in that   10. At least a portion of the reflector is spaced from the inner surface of the housing The muffler according to claim 9, wherein the muffler is provided.   11. The housing releases the exhaust gas from the housing and It has an outlet with a louver that directs the treated exhaust gas away from the engine. The muffler according to claim 1, wherein:   12. The treated exhaust gas emitted from the housing is introduced into the louver. An opening is created for creating a low pressure area and allowing the louver to enter atmosphere into the low pressure area. For mixing the atmosphere with the treated exhaust gas and cooling the treated exhaust gas. The muffler according to claim 11, wherein the muffler is rejected.   13. In a muffler for coupling to the exhaust port of an internal combustion engine,   A housing having an inner surface;   An outer surface within the housing and defining a first chamber, and an inner surface, and A first hollow body having an inlet for introducing exhaust gas into the first chamber;   A catalyst device in the first chamber for heat-treating the exhaust gas;   Comprising a second hollow body within the housing and having an inner surface and an outer surface, Of the first hollow body so that the inner surface of the second hollow body partially defines a second chamber. For cooperating with said outer surface, said outer surface of said second hollow body partly defining a third chamber Cooperating with the inner surface of the housing;   The first hollow body has an outlet with fluid communication between the first chamber and the second chamber. And the second hollow body has an outlet with fluid communication between the second chamber and the third chamber. And the housing has an outlet for discharging exhaust gas from the third chamber. A muffler characterized by having.   14． The treated exhaust gas is introduced into the second chamber through the outlet of the second hollow body. Is arranged to flow substantially across the outer surface of the first hollow body. A muffler according to claim 13.   15. Treated exhaust having the outlet of the second hollow body flowing into the second chamber A louver adapted to direct the treated exhaust gas in substantially the opposite direction of the gas The muffler according to claim 14, wherein the muffler is provided.   16. The inlet of the first hollow body is located adjacent an exhaust port and The outlet of the first hollow body is arranged in the direction in which the exhaust gas separates from the exhaust port. Located away from the exhaust port and the inlet to flow through one chamber The muffler according to claim 13, characterized in that   17． The outlet of the second hollow body directs the treated exhaust gas toward the engine An end of the second hollow body adjacent to the engine so as to flow through the second chamber The muffler according to claim 16, wherein the muffler is arranged in a part.   18. The treatment is performed in a direction in which the outlet of the second hollow body is substantially separated from the engine. A louver adapted to direct the spent exhaust gas. A muffler according to item 17 of the above.   19. It further comprises a flame suppression screen across the outlet of the second hollow body. The muffler according to claim 13, wherein:   20. The first and second hollow bodies are shaped substantially tubular and the muffler is further From a reflector closing the ends of the first and second hollow bodies opposite the engine The muffler according to claim 13, wherein:   21. The reflector plate is spaced from the inner surface of the housing The muffler according to claim 20.   22. The treated exhaust is discharged in a direction in which the outlet of the housing moves away from the engine. 14. A louver for directing air and gas according to claim 13. The muffler mentioned.   23. The treated exhaust gas exiting the outlet of the housing is To create a low pressure region within the louver and for the louver to enter atmosphere into the low pressure region Mixing the atmosphere with the treated exhaust gas and opening the treated exhaust gas The muffler according to claim 22, wherein the muffler cools the gas.   24. In a portable tool powered by an internal combustion engine,   A cylinder equipped with an exhaust port for releasing exhaust gas from the cylinder after combustion Internal combustion engine having;   Heat treatment of the housing, the first hollow body in the housing, and the exhaust gas And a first hollow body defining a first chamber. Inner surface, an outer surface defining a second chamber, the first chamber for introducing exhaust gas into the first chamber An inlet having fluid communication between the second chamber and the second chamber, and treated exhaust gas to the first chamber. Providing fluid communication between the first chamber and the second chamber for communicating from one chamber to the second chamber A second hollow chamber, and the processed exhaust gas in the second chamber is in the second chamber. Of the first hollow body opposite the outlet so as to flow substantially across the outer surface of the first hollow body. Muffler with mouth; and   It is characterized by comprising fixing means for maintaining the muffler with respect to the cylinder. A portable tool to collect.   25. The muffler further defines the first hollow body to define the second chamber. An inner surface cooperating with an outer surface, cooperating with the inner surface of the housing to define a third chamber Front with an outer surface and an outlet with fluid communication between the second chamber and the third chamber The second hollow body in the housing, the outlet of the second hollow body being the treated The exhaust gas is arranged to flow substantially across the outer surface of the hollow body. 25. The portable tool according to claim 24, characterized in that:   26. The first hollow body inlet of the muffler is located adjacent to the exhaust port Then, at the outlet of the first hollow body, the exhaust gas is substantially separated from the exhaust port. Away from the inlet and the exhaust port to flow through the first chamber in a direction 26. The portable tool according to claim 25, characterized in that it is arranged in a   27. Exhaust gas treated at the outlet of the second hollow body of the muffler is substantially directed to the engine Adjacent to the engine to flow through the second chamber in a counter direction 27. Portable according to claim 26, characterized in that it is arranged at the end of an empty body. Naive tool.   28. The second hollow body outlet of the muffler is moved forward in a direction substantially away from the engine. Characterized in that it comprises a louver adapted to direct the treated exhaust gas A portable tool according to claim 27.   29. Flame suppression screen where the muffler further crosses the outlet of the second hollow body. 26. A portable tool according to claim 25, characterized in that it comprises a connector.   30. The muffler housing releases the exhaust gas from the housing and An outlet with a louver that directs the treated exhaust gas substantially away from the engine A portable tool according to claim 25, characterized in that it comprises:   31. The treated exhaust gas emitted from the housing is introduced into the louver. An opening is created for creating a low pressure area and allowing the louver to enter atmosphere into the low pressure area. For mixing the atmosphere with the treated exhaust gas and cooling the treated exhaust gas. 31. A portable tool according to claim 30, characterized in that it is rejected.